In his most specific comments to date about how soon he will meet the call for up to 20,000 more troops in Afghanistan, Gates said he will not have to cut troop levels further in Iraq to free up at least two of those three brigades for Afghan duty.

At the same time, Gates said a key "course correction" in the Afghanistan war for the administration of President-elect Barack Obama will be to build up the Afghan army and better cooperate with Kabul on security operations.

"I think there's a concern on the part of some of the Afghans that we sort of tell them what we're going to do, instead of taking proposals to them and getting their input and then working out with them what we're going to do, so it's a real partnership," Gates told reporters traveling with him to Afghanistan. "That's an important aspect of this, that I think we need a course correction."

McKiernan told reporters after the meeting that he believes the U.S. and its allies need to make a sustained commitment of troops over the next three or four years. He would not say whether that would be at the expected level of close to 50,000 U.S. troops - the current total plus the additional 20,000 he has asked for.

Asked about where additional troops might be deployed, he said, "I think the area that we need to increase our security presence the most in this country is in the south and southwestern parts." Kandahar is in the south of Afghanistan.

Standing outside the headquarters of Regional Command South in Kandahar, Gates said, "This is a long fight, and I think we're in it till we are successful along with the Afghan people."

Asked how many troops that means, Gates said: "I do believe there will be a requirement for sustained commitment here for some protracted period of time. How many years that is and how many troops that is I think nobody knows at this point."

Gates later told a large gathering of troops at a town hall-type meeting that they can expect to see a surge in economic development and other projects in the south.

The meetings come as senior military leaders and the White House are pulling together a broad new military strategy for Afghanistan, one that would shift the focus from the waning fight in Iraq to the escalating Afghan fight.

Gates said he expects the troop levels in Iraq to remain fairly steady through the provincial elections early next year and "probably for some period of time after that."

While there is wide agreement that the military emphasis will now shift to Afghanistan, long regarded as the secondary priority behind Iraq, there is still debate on how best to do it.

McKiernan said Thursday that a key priority is to increase the size of the Afghan army and police. The U.S. has said it wants to double the size of the Afghan army, and McKiernan said he believes it will be three or four years before it is less reliant on international forces.

Gates would not detail any of the findings that have surfaced in strategy reviews. But the push to increase the size of the Afghan army is reflected in at least one of the ongoing studies.

Gates said he has no details on the expected deployments to Afghanistan next year, adding that he has not approved any orders for specific units. He added that he does not know when he will be able to send the fourth requested brigade.

Officials already had announced that one unit - the 3rd Brigade, 10th Mountain Division - would go to Afghanistan in January. But military leaders have resisted identifying the other units or saying when they would go, saying much depends on how quickly troop levels can be cut in Iraq. A brigade is about 3,500 troops.

The U.S. is working to meet deadlines in its agreement with Baghdad that require combat troops to leave the cities by June and be out of Iraq in three years. As planned, the number of combat brigades in Iraq is dropping to 14 early next year, and Gates said that level will enable him to get a second brigade to Afghanistan by summer.

There are 31,000 U.S. troops in Afghanistan, including 13,500 with the NATO-led coalition and 17,500 training Afghan troops and fighting the insurgency. There are 149,000 troops in Iraq.

Gates' stop in Afghanistan was designed initially as a farewell tour to visit troops as he prepared to leave office. But that changed when he was asked to stay on by Obama.

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